The light novel does have the romance elements too. Why the tags aren't included in the manhwa is because romance aren't one of the main genres just side one. Spoiler warning ahead for parts of the novel:
Spoiler!
It's basically just building up for their marriage and things like that. It's not the main focus it's just a cute side thing
She/Her, Autistic & Hyperfixated on BL
❥ 19 years old
Reader since 10 feel free to ask for recs.
Isekai & Shoujo lover too ᠀୧
Mainly read SFW and non toxic BL !!